Overtravel plunger actuator



A. R. KOCH OVERTRAVEL PLUNGER ACTUATOR Filed July 5, 1951 ruega,

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United States Patent O OVERTRAVEL PLUNGER ACTUATOR Alfred Richard Koch, Freeport, lll., assiguor to Minneapolis-Honeywell Regulator Company, Minneapolis,

' a corporation of Delaware Application July 5, 1951, Serial No. 235,321

3 Claims. (Cl. 74-503) This invention relates to an actuator for controlling the operation of an alternate action mechanism, such, for example, as a toggle operated switch.

It is an object of this invention to provide a novel reciprocable actuator having incorporated in it means providing for overtravel of its operating parts.

It is also an object of this invention to provide an actuator of novel construction having a reciprocable driving member which may be deflected away from its normal line of action.

Another object of this invention is to provide a novel actuator having a reciprocable operating button and a driving member which may be deflected out of the line of action of the operating button.

Another object of this invention is to provide a novel actuator having a minimum of exposed parts, and which is compact in size and readily adapted for use on switches of standard size and shape.

Another object of this invention is to provide a novel reciprocable actuator whose parts are free to rotate about the line of reciprocation of the actuator without affecting their operation.

A further object of this invention is to provide a novel reciprocable actuator for a toggle-operated switch wherein the actuator is constructed to have overtravel after the toggle has been actuated to its limiting position.

Other and further objects and advantages of the invention will be apparent from the following description of a preferred embodiment thereof.

In the drawings:

Figure l is a cross-sectional elevation of a toggleoperated switch and the actuator of the present invention in its normal position;

Fig. 2 is a top view of the switch of Figure 1 with the cover and actuator removed;

Fig. 3 is a fragmentary sectional view similar to Figure 1 showing the actuator after its operating button has been initially depressed to cause the driving pin to engage the toggle;

Fig. 4 is a view similar to Fig. 3 showing a later position of the actuator after the toggle has been moved by the actuator from one limiting position to the other;

Fig. 5 is a view similar to Fig. 3 showing the actuator at its full overtravel position, and

Fig. 6 is an exploded perspective view of the actuator according to the present invention illustrating the parts of the actuator before assembly.

The switch with which the actuator of the present invention is here shown is enclosed within an insulating housing comprising a base 1 and a cover plate 2. The snap spring system employed in the switch comprises spaced parallel elongated leaf spring tension members 3 and a leaf spring compression member 4 interconnected at an end 5, which is free to move, and a mounted end 6 at which the other ends of the spaced tension members are interconnected. A pair of upper and lower U-shaped anchors 7 and 8, which are formed of conductive material, hold the mounted end of the snap spring and are suitably connected to the external electrical circuit at terminal 9. A transverse bridging arm 10 interconnects the tension members 3 in spaced relation from the mounted ends thereof and at its straight edge 11 forms a pivot for the toggle 12.

The toggle is formed with an upper ridge 13 separating two valleys 14, 15, and a peripheral groove 16 spaced from the toggle pivot and forming a pivotal seat for the free end of the compression member 4. A lower fiat face 2,697,364 Patented Dec. 2l, 1954 ICC 17 is formed on the toggle beyond the groove 16 and is adapted to abut against the base of the switch housing to limit the toggle movement in one direction. A lower at face 18 on the toggle at the other side of the pivot thereof is positioned to engage the housing base to limit the toggle movement in the opposite direction.

A pair of spaced, opposed upper and lower contacts 19 and 20 are suitably iixedly mounted on the base and are connected to the external electrical circuit. A mobile contact 21 is mounted on the free end of the snap spring to be movable between the opposed fixed contacts. The compression member 4 of the snap spring is pivotally supported in bowed compression at its seat 16 on the toggle such that movement of the toggle between its limiting positions moves the compression member through an axis of maximum stress, causing the mobile contact on free end of the snap spring to move with a snap action from a stable position engaging one of the fixed contacts through a position of unstable equilibrium to another stable position engaging the other fixed contact. The

. snap spring remains in this position until the toggle is actuated to return to its original limiting position.

The actuator of the present invention includes a fixed sleeve or bushing 22 formed with a peripheral lower reduced portion 23 which is dimensioned to fit snugly in a hole formed in the housing cover 2 above the toggle. The lower end of the reduced portion 23 is riveted over during assembly to form a bottom flange 23a to retain the bushing in the cover plate 2. Toward its upper end the fixed sleeve is formed with a peripheral transversely protruding portion 24 to define a lower downwardlyfacing shoulder 25 and an upper upwardly-facing shoulder 26. The fixed sleeve is also formed with an internal downwardly-facing transverse shoulder 27 disposed toward its upper end. The periphery of the sleeve is reduced above the upper outer shoulder 26 to form a narrower upper end 28, and the internal bore of the sleeve is smaller above the internal shoulder 27.

A tubular operating button 29 is formed with a closed upper end 30 and a depending tubular portion 31 closely and slidably surrounding the sleeve protrusion 24. During assembly the lower end of the operating button is crimped in around its periphery to form an annular inwardly-extending transverse lip 32 operative to engage the lower sleeve shoulder 25 and thereby limit upward movement of the operating button along the fixed sleeve. The crimped-in lower end of the operating button closely surrounds the lower end of the fixed sleeve and is freely slidable therealong.

A tubular plunger 33 is formed with a closed upper end 34 abutting against the inside of the closed upper end 30 of the operating button and a depending tubular portion 35. Adjacent its upper end the plunger is formed with a peripheral groove 36. As its lower end the plunger protrudes outwardly at 37 to define an upper peripheral shoulder 37a. The lower protruding plunger portion 37 is closely received within the lower portion of the bore formed in fixed sleeve 22 and is slidable therealong, while the upper end of the plunger is closely received within the upper, reduced-diameter bore portion in the sleeve above the internal sleeve shoulder 27.

A split washer 38 is mounted on the upper peripheral groove 36 in the plunger and snugly engages the interior of the operating button 29 at the top thereof. A return coil spring 39 has its lower end seated against the upper peripheral shoulder 26 on the fixed sleeve and has its upper end seated against the lower face of washer 38. The coil spring is under compression to bias the operating button 29 and the plunger 33 to the extreme upper limit of movement along the fixed sleeve 22. The washer also defines an inwardly extending transverse portion on the operating button positioned to abut against the upper end of the fixed sleeve to limit downward movement of the operating button and the plunger along the fixed sleeve.

The tubular plunger 33 is formed with an vintern annular groove 40 adjacent its lower end to receive a washer 41. This groove is formed by turning over the lower lip of the plunger 33 at its lower end during assembly. The driver for engaging the switch toggle includes an elongated stem 42 which depends below the plunger and an integral enlarged transverse head 43 retained within the tubular plunger by the washer 41. A tubular guide member 44 is formed with a lower outwardly extending flange 45 which bears against the fiat upper face of driver head 43. An overtravel coil spring- 46- is received closely within the tubular plunger, with its upper end seated against the closed top of the plunger and its lower end` seated against the top ofV the lower flange 45- on the guide member'. The upstanding tubular portion of the guide member is closely received within the` convolutions of coil spring 46.

In the operation of the invention, with the toggle and snap spring of the switch in the position of Fig. l, the operating button 29 is depressed to move the lower rounded end of the driver 42 into engagement with the inclined toggle surface between the upper ridge 13 and the valley 14 thereon. The lower end of the driver stem 42 rides down this inclined surface into the valley at 14, at which position the driver is tilted from its normal line of reciprocation, as shown in Fig. 3.

As further downward movement of the operating button 29 and the tubular plunger 33 takes place any further downward movement of driver 42 is limited by its engagement with the toggle. The driver 42 is tilted even further to rotate the toggle 12 about its pivot 11 and effect the snap action movement of the mobile switch contact 21 away from upper fixed contact 19 into engagement with lower fixed contact 20. The downward movement of the operating button 29 along fixed sleeve 22 of course results in compression of the return coil spring 391 Also, the overtravel of the operating button 29 and the tubular plunger 33, after downward movement of the driver has been stopped by` completion of the toggle movement, causes the driver. head 43 and guidel member 44 to be displaced upward within the bore of theplunger to compress the overtravel coil spring 46 positioned therein. The concurrent tilting of theV driver stem 42 isnot directly transmitted to the coil spring 46 because of the interposition of the separate guide member 44 disposed between the coil spring and the driver head 43. Because the overtravel coil spring 46 closely surrounds the upper end of the guide member 44 and because the plunger 33 closely surrounds the spring 46, the overtravel coil spring effectively restrains any tendency of the guide member 44 to tilt substantially and the guide member moves substantially directly upward Within the tubular plunger to effect substantially equal compression of the nvertravel spring 46 around the circumference ofthe after.

During continued overtravel of the operatingbutton 29 during depression thereof the tubular plunger 33 continues to move downward relative to the driver 42, sol

that the overtravel spring 46 within the plunger iscornpressed further. Overtravel of the operating4 button is limited by washer 3S abutting. against the top of the fixed upward.A thel overtravel spring-46 acts against the driver-` head 43 to return the latter to its normal positionseated against washer 4l. When fully retractedthe actuator again assumes the position shown in Fig.4 l. The toggle remains in the position to which it has been displaced until the next time the actuator is depressed.

By virtue of the described-construction and mode of operation ofthe illustrated form ofthe invention, there is provided a reciprocable switch actuator whose switchv engaging portion is operative to be defiected by engagement with the switch operator away from the path of reciprocation of the actuator, while the operating button of the actuator overtravels along'its path of reciprocation. in addition, the entirey actuator is compact in size, has a minimum of exposed parts, andr positions all of its parts free to rotate about the line of reciprocation of the actuator withontaffectintx its operation.

While there has been disclosed a preferred form of the actuator of the present invention and a particular. use thereof in an alternate action, snap-acting switch, it is to be understood that variations in the illustrated form of the actuator may be resorted to without departing from the spirit and scope of the invention.

I claim:

1. I'n an actuating mechanism, in combination, a fixed sleeve formed with an outer peripheral protrusion intermediate its length defining a lower continuous downwardly-facing transverse peripheral shoulder and an upper continuous upwardly-facing transverse peripheral shoulder, an operating button comprising a closed upper end and a depending tubular portion enclosing said fixed sleeve and slidablev therealong and formed with an inturned lower end operative to abut against said lower shoulder on` the fixed. sleeve to limit upward movement of the operating button along the fixed sleeve, a plunger slidably disposed within said fixed sleeve and formed with an upwardly-facing transverse shoulder, said fixed sleeve being formed intermediate its length with an internal downwardly-facing transverse shoulder interposed in the path of upward movement of said plunger shoulder and located along the sleeve to limit upward movement of said plunger, an' annular washer' carried on the* upper end of said plunger and snugly received' within said operating button at the upper end thereofl and operative to engage the upper end of the fixed sleeve to limiti downward movement of the plunger and the operating button therealong, and a coil spring disposed in the annular space surrounding said plunger and enclosed within said operating button, said coil spring having its lower' end seated against said upper shoulderon the fixed sleeve and having its upper end seated against said washer, said coil springbeing under compression between saidupper sleeve shoulder and saidY washer to resiliently urge the operating button and the plunger to the extremeupward limit of movement thereof along the fixed sleeeve.

2. An actuating mechanism comprising the combination of a fixed sleeve formed with an outer protrusion intermediate its length to define' a lower downwardlyfacing shoulder, an upper upwardly-facing shoulder spaced tlie'reabove, and narrower peripheral sleeve portions' above and below-'said protrusion, an operating button comprising a tubular depending portion disposed about said fixed sleeve to be slidable therealong and formed with inturned transverse protrusionstat its lower end operable to'enga'g'e said lower shoulder onthe fixed sleeve to' limit upward movement of thev operating button along the fixed sleeve, an inwardly-extending abutment portion positioned toward' the upper' endof the operating button and movable in unison therewith operative tol abut against the upper end ofthe fixed sleevel to limit downward movement of the operating button along the fixedV sleeve, aV returnl coil spring under compression betweent saidupper shoulder' on the fixed sleeve and said abutment portion on the operating button to resiliently urge said operating button to its upward limit of movement along the fixed sleeve, a hollow plunger reciprocable Within the fixed sleeve andy movable' in unison with the operating button, said plunger being formed with an inwardly-extending transverse portion adjacent its upper end and an inwardly-extending transverse annular portion adjacent its lower end, a driver formed with a' stem extending downward through said inwardly-extending annular portion at the lower end of the tubular plunger and formed'with an enlarged transverse head positioned loosely within said tubular plunger above said inwardlyextending annular'portion at the lower end thereof, a separate guide member disposedabove said head on the driver and positioned slidably within said tubular plunger and formed with a neck extending upwardly within said tubular plunger, andan overtravel coil spring within' said tubular plunger under compression between said inwardlyextending transverse portion adjacent the upper end thereof and said guide member to resiliently urgesaid head on the driverdownward into abutting relation with said inwardly-extending annular portion at the lower end of the tubular plunger, said overtravel coil spring closely surrounding said neck on the guide member to restrain tilting of the guide member when the driver is tilted.

3. An actuating mechanism comprising the combination of a fixed sleeve formed with an outer peripheral protrusion intermediateY its length defining a lower' downwardly facing transverse shoulder and an upwardly facing transverse shoulder, an operating button' comprising a closed upper end and a depending tubular portionclosely surrounding said outer protrusion on the fixed sleeve and slidable' therealong and formed with an inturned lower end operative to abut against said lower shoulder on the fixed sleeve to limit upward movement of the operating" button along the fixed sleeve, a reciprocable tubular plunger slidably disposed within said fixed sleeve and at its upper end abutting against the closed upper end of the operating button, an annular washer carried on the upper end of the plunger and snugly received within said operating button at the upper end thereof and operative to engage the upper end of the ixed sleeve to limit downward movement of the plunger and the operating button along the fixed sleeve, a return coil spring disposed in the annular space surrounding said plunger and disposed within said operating button, said return coil spring having its lower end seated against said upper shoulder on the xed sleeve and having its upper end seated against said washer, said return coil spring being under compression to resiliently urge the operating button and the plunger to the extreme upward limit of movement thereof along the fixed sleeve, said tubular plunger being closed at its upper end and at its lower end carrying an inwardly-extending annular washer, a driver formed with an elongated stem extending downward through said inwardly extending washer and formed at its upper end with an enlarged transverse head disposed loosely within said tubular plunger above said inwardly extending washer at the lower end thereof, an overtravel coil spring disposed closely within said plunger and having its upper end seated against the closed upper end of the plunger, and a guide member formed with an upward1yextending neck received closely within said overtravel coil spring and a lower outwardly-extending annular ange abutting against the lower end of the overtravel coil spring, said guide member being separate from said stem and being resiliently urged by the overtravel coil spring to engage said head on the driver and urge the driver downward, said guide member being operative to move substantially directly upward within the tubular plunger to equalize the compression on the overtravel coil spring in response to tilting movement of the driver.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 871,110 Comings Nov. 19, 1907 1,051,219 Graban Ian. 21, 1913 1,569,416 Bates Jan. 12, 1926 1,935,234 White Nov. 14, 1933 2,047,950 Douglas July 21, 1936 2,295,484 Krieger Sept. 8, 1942 

